On Wed, Jul 20, 2011 at 05:15:42PM -0700, Jeremy Allison wrote: > On Wed, Jul 20, 2011 at 08:07:58PM -0400, J. Bruce Fields wrote: > > On Fri, Jun 10, 2011 at 09:48:59AM -0400, J. Bruce Fields wrote: > > > On Fri, Jun 10, 2011 at 09:56:49AM +0200, Volker Lendecke wrote: > > > > Without having looked too deeply, just let me point out that > > > > Samba here has a plain flaw. Early Linux Kernel versions > > > > that we programmed against did not properly support read > > > > only leases, so we did not implement that initially. If I > > > > remember correctly we never got around to finally do it once > > > > it became available. Eventually we will probably, as read > > > > only leases are a pretty important feature to present to > > > > CIFS clients. > > > > > > Thanks, I didn't know that. (Or I did, and I forgot.) > > > > > > When you *do* implement that, is there any chance you'd have this need > > > to be able to downgrade to a read lease in the case of a conflict? > > > > So it's a question about the protocols samba implements: > > > > - Do they allow an atomic downgrade from an exclusive to a > > shared oplock? (Or to a level 2 oplock, or whatever the right > > term is). > > Yes. Exclusive can go to level 2 - in fact that's the default > downgrade we do (unless an smb.conf option explicity denies it). > > > - If so, can that happen as a response to a conflicting open? > > (So, if you're holding an exclusive oplock, and a conflicting > > open comes in, can the server-to-client break message say "now > > you're getting a shared oplock instead"? Or is the client > > left without any oplock until it requests a new one?) > > Yes, this can happen. > > In SMB, we only break to no lease when a write request comes > in on a exclusive or level2 oplock (read-lease) handle. Ok, thanks, that means we need a more complicated fix here--I'll work on that.... --b. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
